Hi! I'm sorry that you sil is having to go thru this. I had several different wigs that I would wear only when I would go somewhere that I felt it was necessary to look "normal". Heck, not only didn't I wear my wig much I also didn't wear my prothesis. Hated both of them.
The hats and scarves that have the hair attached at the bottom are great. You might want to suggest that she go to her beautician before she loses her hair and see what she/he suggests. There are wigs that are very lightweight. Tell her to make sure that she does have something on her head in the sun as the scalp can burn very quickly. Also, her insurance will probably pay for the wig if she uses the phrase "hair prothesis".
Deb